Preheat your oven to 350°F. Add the torn bread to a baking sheet. In a small bowl mix the oil, butter, salt, pepper, and garlic powder. Toss the bread with the butter mixture right on the baking sheet - no need to get a bowl dirty. Sprinkle the grated cheese over the bread.
Bake for 7 minutes, give the croutons a good stir and bake for another 3-5 minutes. The croutons are done once the crust-less pieces are mostly dried out but still have a slight give. They will continue to dry out more as they cool, and you don't want croutons that are super hard, so try not to overbake them.